1. Field of the Invention
The present invention relates to the field of flying missiles and more particularly to a novel means for stabilizing the flight of an elliptical object such as a ball by providing a selective, arrangement of weighted mass about the midsection of the object.
2. Brief Description of the Prior Art
Conventional elliptical, inflated spheroids such as footballs are considered unstable in flight from their point of launch to a remote target point. In order to stabilize the missile's flight as much as possible, a high spin speed is induced into the missile so as to reduce small pointing errors or induced nutation along its path of travel. Considerable skill is required of a person who manually induces flight to the missile and an improperly launched ball exhibits unstable behavior which typically worsens from the beginning of flight to the end of the ball's travel. Types of unstable flight behavior which is unacceptable are due to insufficient spin speed or errors in initial conditions which result in nutation or precession since spin axis fails to track or maintain course on the tangent to the flight path. In other words, the missile fails to stabilize at .theta.=0.
Precession and nutation characteristics of the missile dominate its dynamics and spin axis will not converge at .theta.=0 even though average position does track flight path.
Furthermore, external torque is induced into the missile from impinging wind or ram air coupled with initial transverse rates such as encountered with an improper launch. This will usually tend to make the instability of travel increase. If precession and nutation are created such that resultant viscous damping forces from air and control of precession and nutation angle is optimized, the missile tends to stay on tangent flight path and therefore experiences perturbation and follows in a stabilized path where precession and nutation are suppressed.
Therefore, a long-standing need has existed to provide a novel stabilizing means for an elliptical spheroid, inflated or not, which overcomes the inherent problems of precession and nutation encountered with conventional elliptical spheroids by optimizing dynamic properties and coupling to viscous air drag to thus suppress transverse rates such as precession and nutation. Such a missile may incorporate the critical placement of weighted masses within the enclosure of the missile about its midsection so that the missile will travel along its transverse path maintaining utmost stability about its longitudinal axis.